This invention relates to a longitudinal seam welding apparatus for use in seam welding a longitudinal joint of a cylindrical main body of an electric motor frame.
FIGS. 1 and 2 illustrate one example of a longitudinal seam welding apparatus which has heretofore been used in seam welding the joint of a cylindrical main body of an electric motor frame. The conventional seam welding apparatus comprises a pair of clampers 1 and 2 pivotally mounted on a bed 3 by a pin 4. The clampers 1 and 2 are movable between their open position and closed position (the closed position being shown in FIGS. 1 and 2) by the respective hydrualic cylinders 5 and 6. In the closed position, the clampers 1 and 2 firmly hold therebetween a frame main body 7 which is a wound steel sheet with its seam or joint 8 positioned at the top. The apparatus also comprises a centering pin 9 which extends downwardly from a column 10 so that the centering pin 9 may be inserted into the gap of the joint 8 of the frame main body 7. The apparatus comprises a welding torch 11 which is also supported by the column 10 for forming a weld seam along the longitudinal joint 8 of the frame main body 7.
In the conventional seam welding apparatus of the above construction, there are a number of parts that must be moved during the welding operation. Accordingly, the number of parts is relatively large and the structure of the welding apparatus is complex, rendering the apparatus expensive. Also, since the number of steps for achieving the seam welding is considerably great, a relatively long period of time is necessary for welding.